The present invention relates generally to simulating anatomical conditions of a patient for MR applications evaluation and, more particularly, to an apparatus and method for simulating brain properties for improved MR scanner calibration and pulse sequence design.
To properly develop and test imaging protocols and techniques it is necessary for radiologists, researchers, software design engineers, and technicians to accurately and precisely simulate imaging conditions including general anatomical conditions of a typical patient. Known techniques include the use of animals to simulate the anatomical conditions of a human patient. Using animals to create a sample test condition has a number of disadvantages.
First, acquisition and care of animals often requires extensive and continual expenditures. Animals must be properly cared for and fed to maintain the health of the animal but also to be compliant with a number of regulations associated with animal testing. Further, in the absence of a well-trained animal, it is often necessary to sedate the animal, otherwise the animal may be uncooperative in simulating the test conditions. Moreover, the social climate associated with using animals and testing laboratories may be such that a company or research group may be publicly adversely affected by the use of animals in medical testing.
Additionally, researchers and design engineers forfeit a certain amount of control over the testing conditions by using animals to simulate human anatomical conditions. For example, without using expensive and potentially detrimental drugs to simulate precise human anatomical patterns, researchers and software designers are unable to exactly define and control the anatomical conditions, such as, defining brain activity. That is, researchers cannot reasonably force data to precisely mimic data taken from a human brain scan. Further, it is considerably more difficult for researchers and software engineers to repeat particular conditions using live animals.
While animals may be a viable alternative for mimicking certain human physiology and physiologic activity, the human brain is not reproduced in these species. As such, testing must be done on human test subjects. The requirement for human volunteers is often difficult to arrange, requires extensive regulatory approval, and presents a large measurement variation.
The use of phantoms presents a second alternative to human testing. Scanning of a phantom alleviates most of the considerations associated with animal or human test subject scanning. Known phantoms however do not accurately mimic the human brain. Such existing phantoms do not exactly differentiate the proton densities between white matter and gray matter of the human brain. Consequently, an optimum flip angle, which is proton density sensitive, for such phantoms, is typically set to 90 degrees for a T1-weighted spin-echo imaging. It has been shown that the optimum flip angle for human scanning is not always 90 degrees to maximize the tissue contrast. An accurate flip angle provides image contrast between white matter and gray matter of human brain scans that take into account proton density differences. As such, pulse sequence generation and machine calibration for human brain scanning is not optimized since current brain phantoms do not differentiate between white matter and gray matter proton densities. Additionally, the optimal flip angle for contrast may very depending upon the specifics of the pulse sequence. That is, the optimal flip angle may be more or less than 90 degrees depending upon the particular MR study.
Therefore, it would be desirable to design an apparatus and method for simulating a human brain that allows for optimization of the pulse sequence parameters GMSGEMS Let”s make this more general. The invention is not only for T1-weighted imaging sequences. or scan protocols.